Typescript class deserialization (using JSON.parse() and public properties)

ts-class-deserialize.ts

const json = `{
  "type": "two",
  "value": 25.5,
  "items": [{
    "order": 2,
    "value": "hello"
  }, {
    "order": 5,
    "value": "bye"
  }]
}`;

enum Type {
  One = 'one',
  Two = 'two',
  Three = 'three',
}

class Item {
  constructor(
    public order: number,
    public value: string,
  ) { }
}

class Data {
  constructor(
    public type: Type,
    public value: number,
    public items: Item[],
  ) { }

  public doSomething(): void {
    console.log('Doing...', this.type, this.value, this.items.length);
  }
}

function main() {
  const data: Data = JSON.parse(json);

  console.log(data);

  data.doSomething(); // ERROR: not really an instance

  console.assert(data.type === Type.Two);
  console.assert(data.value === 25.5);
  console.assert(data.items.length === 2);
  console.assert(data.items[0].order === 2);
  console.assert(data.items[0].value === 'hello');
  console.assert(data.items[1].order === 5);
  console.assert(data.items[1].value === 'bye');
}

main();